Diff: mdot/WakeUp.h

Revision:

3:63d10f2375ea

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mdot/WakeUp.h	Fri Sep 14 15:39:09 2018 -0500
@@ -0,0 +1,98 @@
+#include "mbed.h"
+
+/**
+ * Class to make wake up a microcontroller from deepsleep using a low-power timer. 
+ *
+ * @code
+ * // Depending on the LED connections either the LED is off the 2 seconds
+ * // the target spends in deepsleep(), and on for the other second. Or it is inverted 
+ * 
+ * #include "mbed.h"
+ * #include "WakeUp.h"
+ * 
+ * DigitalOut myled(LED1);
+ * 
+ * int main() {
+ *     wait(5);
+ *
+ *     //The low-power oscillator can be quite inaccurate on some targets
+ *     //this function calibrates it against the main clock
+ *     WakeUp::calibrate();
+ *    
+ *     while(1) {
+ *         //Set LED to zero
+ *         myled = 0;
+ *         
+ *         //Set wakeup time for 2 seconds
+ *         WakeUp::set_ms(2000);
+ *         
+ *         //Enter deepsleep, the program won't go beyond this point until it is woken up
+ *         deepsleep();
+ *         
+ *         //Set LED for 1 second to one
+ *         myled = 1;
+ *         wait(1);
+ *     }
+ * }
+ * @endcode
+ */
+class WakeUp
+{
+public:
+    /**
+    * Set the timeout
+    *
+    * @param s required time in seconds
+    */
+    static void set(uint32_t s) {
+        set_ms(1000 * s);
+    }
+    
+    /**
+    * Set the timeout
+    *
+    * @param ms required time in milliseconds
+    */
+    static void set_ms(uint32_t ms);
+    
+    /**
+    * Attach a function to be called after timeout
+    *
+    * This is optional, if you just want to wake up you 
+    * do not need to attach a function.
+    *
+    * Important: Many targets will run the wake-up routine
+    * at reduced clock speed, afterwards clock speed is restored.
+    * This means that clock speed dependent functions, such as printf
+    * might end up distorted.
+    *
+    * Also supports normal way to attach member functions
+    * (not documented for simplicity)
+    *
+    * @param *function function to call
+    */
+    static void attach(void (*function)(void)) {
+        callback.attach(function);
+    }
+
+    template<typename T>
+    static void attach(T *object, void (T::*member)(void)) {
+        callback.attach(object, member);
+    }
+    
+    /**
+    * Calibrate the timer
+    *
+    * Some of the low-power timers have very bad accuracy.
+    * This function calibrates it against the main timer.
+    *
+    * Warning: Blocks for 100ms!
+    */
+    static void calibrate(void);
+
+
+private:
+    static FunctionPointer callback;
+    static void irq_handler(void);
+    static float cycles_per_ms;
+};
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